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group By hAving mAx

直接select max(num) 再group by 就行 不用后面的having

select a.* from table a, (select 姓名,max(开始日期) 日期 from table group by 姓名) b where a.姓名=b.姓名 and a.开始日期=b.日期

select cno from score group by cno having degree

MIN(), MAX()是聚合函数. group by 后面是要跟着的 select 中所有不是聚合函数的字段。 ex1: select count(*) from emp; //只是查询总总数 emp这张表里一共有多少条记录 所以不用group by ex2: select count(*) , deptno from emp group by dept...

1、聚合函数可以嵌套2次,所以max(avg(sal))没有问题。 2、提示ORA-00937: not a single-group group function,是因为这已经是两层关系了。进行拆分就是: select max(a.str_avg),a.deptno from (select avg(sal) as str_avg,deptno from emp g...

UPDATE W SET W.A = ( SELECT W.A - S.A from S where W.G = S.G and S.N in(SELECT max(N) FROM S group by G ) ) where exists (select 1 from S where W.G = S.G and S.N in(SELECT max(N) FROM S group by G ) ) exists 语句很重要,否则如...

(1)一般而言在group by语句中,的结果显示只能是分组字段,如果有其他字段那么必须是带有聚合函数的,比如count,sum,max,min等,但是这里直接放个*就可以执行了? (2)如果是在group by之前筛选,那么怎么count,是选择oid=5的进行count么?...

1 select * from (select nodecol,count(*) counts from tmp3 group by nodecol) twhere counts=(select max(count(*)) from tmp3 group by nodecol) 2 select * from tmp3 where nodecol in(select t.nodecol from (select nodecol,count(*) co...

select max(id) id, send_id, receiver_id from messages where receiver_id='3' group by send_id, receiver_id order by id desc limit 0,10

一、 聚合函数: sql语言中一种特殊的函数:聚合函数,SUM, COUNT, MAX, MIN, AVG等。这些函数和其它函数的根本区别就是它们一般作用在多条记录上。 SELECT SUM(population) FROM COUNTRY 这里的SUM作用在所有返回记录的population字段上,结果就...

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